Method of forming the rim members of sheet-metal pulleys



E. G. LARSON AND J. T. SDERSTRM. METHOD OF FORMING THE RIM MMBERS OFSHEET METAL PULLEYS.

Patented Jan. 25, 1921;

2 SHEETS-SHEET h E. G. LARSON AND u. SDERSTROM. METHOD or rommc THE mmMEMBERS or SHEET mam PuLLYs. APPLICATION FILED 16.21, 1919.;

1, 64 67 P at M 25.1 .2

` M IjrEN'I'ORS; 17 95;

UNETED STATE QEFICE.

EEIK answer LABSON, or GOTTENBORG, AND JOHAN rnonon SDERSTRM, OFnnrnrnnnomr, SWEDEN, nssronons ro AKTIEBOLAGET SVENSKA KULLAGER-FABRIKEN, or sorrnmone, sw'nnnn, e oenronerron or SWEDEN.

METHOD OF OEMING THE BIM MEMBERS OF SHEET-METL PULLEYS.

To call 7,071 om it may cancer 17,:

Be it known that we, Earn GUs'rAr LAR- soN and JOHAN Tronoi lonnsrnn,subjects ot' the Kin ot' Sweden, residing, respeciivelm at (i ottenborg,Sweden, and at Katrineholm, Sweden, have iuvented a new and useful`Improvement in Methods of ,Formin' the Bim l'enibers of Sheet-MetalPulleys, of' which the 'following is a speciication. i

The present inventon relates to a method of produeing a eonvex or eurvedprofile oi' the rim member of sheet metal pulleys. The face or peripheryof .pu lleys hasas e rule a convex profile in order to prevent the beltfrom slipping oi. The present invention relates to a simple method ofproducng such convex profile of the :face or periphery of sheet metalpulleys in which the rim niember consists of a sheet metal band placedaround a spider or spoke member.

The .present method is broadly `characterized by this that the bandwhich is to form the rini, is introdneed between a punch 'and acorresponding die and is pressed and successively fed between said punchend said die so that owing to the pressing the band obtains the desi redconyex profile. tic'e the said pressing may be performed on rini membersthe ends of which are buttjointed as well as on rim members which areprovided at the joint with flanges bent inward for seem-ing the rimmember to the spider or spoke member. ;in the first named instance 'the.metal band is first bent so that it obtains the :proper curvaturecorresponding to the diameter of ,the pulley, which bending may beeiiected 'for instance in a rolling apparatus having three rolls theupper oneof which is adjnstable. The band is afterward fed between thepunch and the die for producing the convex profile. the other hand, ifthe rim member is provided wLith jointing fianges bent inward, it issuitable, before the rim member is pressed to conyex profile tocorrugate or slit the said fianges so that they permit the portions oi'said fianges 'to the rini ?member adjacent Ti the jontng acqnire theconyex profile.

flanges are plaited or eorrugated and thns not slitted this operationwill produce a certain arching of the rim member in the Via-inity of thefianges Whenlthe jonting fianges have been made corrngated the sheetmetal Specificaton of Letters Petent.

Tn prac-' Pzitented J an. 25, 1921.

Application filed August 21, 1919. Serial No. 3185393.

'the metal into approximetely the segment of a cyliuder preferably aftersuch formation of .the fianges; and finally pressing the conte): portionof the rini member to mpart to it a profile which is conveX in a planeCoincident with the axis around which the pulley is to turn.

The means 'or pressing the rim member to the desired convex profileconsists principally of a punch and a corresponding die the workingsurfaces of which punoh and die hare the seine curvatures inthe centralplane of sherim member as the inner and' outer suraces of the mountedrim member, while in the axial plane they have greater curvatures thanthe desired COnVBX profile of the rim inember. This latter feature isnecessary since after the pressing the rim member always fiattens outsomewhat owing to the elasticity of the material. The means for plaitingor' corrugating the jointing fianges `consists suitably in similarmanner of a p nch and e die one of which is pro- `vided with one or morepreferebly Wedgeshaped projections and 'the other of which is providedwith one or more correspondingly sheped grooves. y

The aeeompanying drawings llustrate by way oi' example one embodiment ofthe firstmentioned means and one embodiment of ;the last mentionedmeans. Figure 1 shows a side View of the means for produeing the convexprofile of the rinrniember, and 2 shows an edge View of the said means.Fg. shows a'side View of the means for producing the corrugatiens.

The means for producng the eenvex profile consists of the punch 'l andthe .corresponding die 2 The `punch l is provided with a groove 3 inorder to provide against pressing down of guidng knobswhich arepreferably provided in the rim member for guiding said member on thespider'or spoke member. Otherwise the punch has the shape of two conesthe bases of which abut. The curvatures ofthe punch and of the die inthe central plane of the rim member are equal to the desired curvaturesof the nner and outer surfaces of the rim member 4:, whereas the concaveangle between the bounding lines in the axial plane of the rim member isslightly smaller than the desired angle, in view of the elasticity ofthematerial.

'If desired, the punch 1 may, of course, be shaped in such manner thatthe section of the punch in a plane through the axis of the 'rim memberis bounded by a circular curve instead of two straight lnes, as shown inFig. 2. The radius of said circular curve shall in such case besomewhatsmaller than the radius of the final curvature.

The means for corrugating shown in Fig. 3 consists of a punch 5 and adie 6. The punch 5 is adjustable in lateral direction and is provided inthe working surface directed toward the die with a semi-circular orwedgeshaped projection 7, which is largest at the bottom and tapers intoa point at the upper edge ofth'e working surface. The die 6 is providedwith a groove 8 corresponding to the proj'ection 7. The punch 5 isSecured to a reciprocating slide-block 9 which is guided in a guide 10.The movement of the slide block toward the die is produced by means of awedge ll which is movable in vertical direction and bears against aroller 12 ournaled in the slide block. A coil spring l is insertedbetween the slide-block 9 and the portion 13 of the guide 10 supportingthe die 6, which spring becomes compressed when the slide block is movedagainst the die and moves the slide-block back to initial position whenthe wedge 11 moves upward.

The rim member 15 is placed over the portion 13 so that its fiange 16covers the work ing surface of the die 6. W hen the punch is movedagainst the fiange the desired corrugation is formed in said fiange,and, simultaneonsly, the portion of the rim member adjacent the flangeobtains a slightly conveX or arched shape. `When the fiange has beencorrugated the rim member is bent to the proper curvature and is finallypressed with the apparatus shown in 'l and 2, so that it obtains thedesired convex shape.

It will be understood that the punch 5 may also be provided with severalprojections 7 adjacent one another and the die 6 with a correspondngnumber of slots 8, so 'that several plaits or corrugations are formed inthe ointng flanges. i

e claim i 1. The method of forming the rim member of sheet metal pulleyswhich consists in turning up the ends of metal bands to form jointingflanges, and convexing the intervening portions of the bands by repeatedpressure between a' punch and die having at their junction a conveXprofile, such pro-` file being a segment of a circle in the plane of thepulley, and being of convex' section in planes coinciding with the axisof the pulley.

2. The method of forming the rim member of sheet metal pulleys whichconsists in convexing a metal band having its ends bent to form jointngfianges by subjecting it between such flanges to pressure between apunch and-die having at their junction a convex profile, such profilebeing a segment of a circle in the plane of the pulley, and being ofconvex section in planes coinciding with the axis of thevpulley, suchpressur being applied repeatedly to different portions of the band.

3. The method of forming the rim member of sheet metalpulleys whichconsists in tnrning up the ends OI" `a metal band to form jointingflanges, shaping such fianges so as to not oppose the convexing of thecontiguous portions of the band in a transverse plane, and thenconvexing the intervening portions of the band by pressure between apunch and die having at their junction a convex profile, such profile*being a segment of a circle in the plane of the pnlley, and being ofconvex section'in planes coinciding with the axis of the pulley, suchpressure being applied repeatedly to difierent portions of the band.

4:. The method of forming the rim meinber of sheet'metal pulleys whichconsists in turning'up the endsof a metal band to form jointingfianges,` then co rrugating such fianges so that they will not opposethe convexing of the contiguous portions of the band in a transverseplane, and then convexing the intervening portions of the band bypressure between a punch and die having at thei-r junction a convex`profile, such profile being a segment of a circle in the plane of thepnlley, and being of conveX section in planes coinciding with the axisof the pulley, such pressure *being'applied repeatedly to differentportions of the band.

5. In the forming' of the rim member of sheet metal pulleys by firstturning up the ends of a metal band to form jointing fianges, and thenconvexing the intervening portions of the band, the step of corrugatingsuch llanges by pressing them between corrugatng dies adapted to crimpthe flanges to a depth continually increasing from the bend to the endof each flange. i

rem GUSTA?, Larsen( jOHAN TEODGR snrksmem.

